Paez-Rubio Tania, Ramarui Abel, Sommer Jeffrey, Xin Hua, Anderson James, Peccia Jordan
Department of Civil and Environmental Engineering, Arizona State University, Tempe, Arizona, USA.
Environ Sci Technol. 2007 May 15;41(10):3537-44. doi: 10.1021/es061786p.
This study measured aerosol emission rates produced during the spreading of dewatered class B biosolids onto agricultural land. Rates were determined in multiple independent experimental runs by characterizing both the source aerosol plume geometry and aerosol concentrations of PM10, total bacteria, heterotrophic plate count bacteria (HPC), two types of biosolids indicator bacteria, endotoxin, and airborne biosolids regulated metals. These components were also measured in the bulk biosolids to allow for correlating bulk biosolids concentrations with aerosol emission rates and to produce reconstructed aerosol concentrations. The average emission rates and associated standard deviation for biosolids PM10, total bacteria, HPC, total coliforms, sulfite-reducing Clostridia, endotoxin, and total biosolids regulated metals were 10.1 +/- 8.0 (mg/s), 1.98 +/- 1.41 x 10(9) (no./s), 9.0 +/- 11.2 x 10(7) (CFU/s), 4.9 +/- 2.2 x 10(3) (CFU/ s), 6.8 +/- 3.8 x 10(3) (CFU/s), 2.1 +/- 1.8 x 10(4) (EU/s), and 36.9 +/- 31.8 (microg/s) respectively. Based on the land application rates of spreaders used in this study, an estimated 7.6 +/- 6.3 mg of biosolids were aerosolized for every 1 kg (dry weight) applied to land. Scanning electron microscopy particle size distribution analysis of the aerosols revealed that greater than 99% of the emitted particles were less than 10 microm and particle size distributions had geometric mean diameters and standard deviations near 1.1 +/- 0.97 microm. The demonstrated correlations of bulk biosolids concentrations with aerosol emission rates, and the reconstruction of aerosol concentration based on PM10 and bulk biosolids concentration provide a more fundamental, bulk biosolids-based approach for extending biosolids aerosol exposure assessment to different land application scenarios and a broader range of toxins and pathogens.
本研究测量了脱水B级生物固体在农田上撒施过程中产生的气溶胶排放率。通过表征源气溶胶羽流几何形状以及PM10、总细菌、异养平板计数细菌（HPC）、两种生物固体指示细菌、内毒素和空气中生物固体中受管制金属的气溶胶浓度，在多个独立实验运行中确定了排放率。还对散装生物固体中的这些成分进行了测量，以便将散装生物固体浓度与气溶胶排放率相关联，并生成重建的气溶胶浓度。生物固体PM10、总细菌、HPC、总大肠菌群、亚硫酸盐还原梭菌、内毒素和生物固体中受管制金属总量的平均排放率及相关标准偏差分别为10.1±8.0（毫克/秒）、1.98±1.41×10⁹（个/秒）、9.0±11.2×10⁷（CFU/秒）、4.9±2.2×10³（CFU/秒）、6.8±3.8×10³（CFU/秒）、2.1±1.8×10⁴（EU/秒）和36.9±31.8（微克/秒）。根据本研究中使用的撒布机的土地施用量，每施用于土地1千克（干重），估计有7.6±6.3毫克生物固体被气溶胶化。对气溶胶的扫描电子显微镜粒度分布分析表明，超过99%的排放颗粒小于10微米，粒度分布的几何平均直径和标准偏差接近1.1±0.97微米。散装生物固体浓度与气溶胶排放率之间已证明的相关性，以及基于PM10和散装生物固体浓度重建气溶胶浓度，为将生物固体气溶胶暴露评估扩展到不同土地施用场景以及更广泛的毒素和病原体提供了一种更基本的、基于散装生物固体的方法。
